More on human-orangutan analysis

[Will Fischer]

On Wednesday, June 25, 2003, at 11:29  PM, John grehan wrote:

> It is my current proposition that humans and chimps are most similar to
> each other in terms of overall similarity and this applies to both gene
> sequences and morphological characters (even though there may not
> always a
> precise match). In terms of shared derived features the weight of
> evidence
> in total proposed morphological synapomorphies is greater for the
> human-orangutan relationship but unfortunately these characters are
> generally excluded from the competing models.

Whether the "proposeed morphological synapomorphies" are REAL
synapomorphies depends on which tree is right.  Each tree will delimit
different groupings of potential synapomorphies, and the job of the
phylogeneticist is to figure out which grouping is to be preferred.
The assignment of character states as apomorphic, synapomorphic,
pleisiomorphic, etc. depends on the tree; the preferred tree is chosen
based on the actual character states, not from a priori judgements
about which character states are synapomorphic.

Am I beating a dead horse here?
_____________________________________________________________
Will Fischer                       wfischer at uts.cc.utexas.edu

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